自带偏置磁路的磁致伸缩合金/石英谐振器复合谐振式磁传感器  

A resonant magnetic field sensor with bias magnetic circuit composed of magnetostricive alloy and quartz crystal resnator

作　　者：彭伟民 卞雷祥[1] 黄子军 李辉 张闯 裴文鹏 PENG Weiming;BIAN Leixiang;HUANG Zijun;LI Hui;ZHANG Chuang;PEI Wenpeng(Nanjing University of Science and Technology,Mechanical Engineering,Nanjing 210094,China)

机构地区：[1]南京理工大学机械工程学院,南京210094

出　　处：《自动化与仪器仪表》2020年第10期1-5,11,共6页Automation & Instrumentation

基　　金：国家自然科学基金重大科研仪器研制专项(No.61527813);中央高校基本科研业务费专项资金(No.30918011201)。

摘　　要：将磁致伸缩材料与石英音叉谐振器复合设计了一种超低功谐振式磁传感器,磁场作用下产生的磁致伸缩力传递至音叉谐振器纵向,引起其频率变化,即磁-力-频率转换实现磁测量。针对所用FeGa合金磁致伸缩效应的非线性特性,采用永磁体设计了一种紧凑结构的小体积偏置磁路,为其提供了合适偏置磁场。通过集总参数方法对偏置磁路进行了建模,并使用有限元软件对沿铁镓合金长度方向的磁感应强度分布进行了仿真。为了减小参数误差对预测的影响,对FeGa处于均匀的磁场中和处于偏置磁路中的2种不同情况,进行了仿真和对比分析。制备器件测试表明:(1)偏置磁路能为传感器提供合适的偏置磁场,与理论结果较吻合;(2)带偏置磁路的谐振式磁传感器在±50 Oe范围内具有较好的线性,非线性误差为3 Hz(1.15%FS),灵敏度为2.6 Hz/Oe,滞后误差为2.6 Hz(1.00%FS),分辨率6 mOe以下。A low-power resonant magnetic sensor is designed by bonding the double-ended quartz crystal tuning fork(DETF)resonator with magnetostrictive plate together.The magnetostrictive force occurring under magnetic field is converted into the longitudinal force in the fork resonator which leads to a change of the resonant frequency of the resonator.Namely,the conversion of magnetic-force-frequency occurs in the composite sensor.In terms of nonlinear magnetostrictive effect of FeGa alloy,a small and compact permanent magnet bias magnetic circuit is designed to provide optimal bias magnetic field for the FeGa element.The magnetic circuit model based on the“lumped parameters”method is established.In addition,the distribution of magnetic flux density along the longitudinal direction of the FeGa alloy is simulated by finite element analysis software.In order to avoid the prediction error caused by parameter errors,the comparative analysis is carried out by observing the magnetic induction intensity of the FeGa alloy in two conditions,i.e.,the FeGa alloy is magnetized in a uniform magnetic field and the designed magnetic circuit,respectively.The experimental results show that:a)the designed magnetic circuit can provide qualified bias magnetic field for the sensor,which are in a good agreement with the theoretical analysis;b)the resonant magnetic field sensor with magnetic circuit shows excellent linear characteristic(non-linearity error of 1.15%FS)over its measurement full scale(FS)of±50 Oe with a sensitivity of 2.6 Hz/Oe,non-linearity error of 3 Hz(1.15%FS)and hysteresis error of 2.6 Hz(1.00%FS),resolution of 6mOe.

关 键 词：谐振式磁传感器 石英音叉谐振器 磁致伸缩材料 偏置磁场 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]